Description of related art: U.S. Pat. No. 4,628,986 issued Dec. 16, 1986 to D. L. Southam discloses a mold making apparatus in which the cope and drag flasks are urged against flask locator stop members external of the flasks and at right angles with respect to one another by right angularly disposed pusher mechanisms. This centers the flasks with respect to patterns located on the support plate. With the mold halves made with greater precision, improved alignment and registration of the mold halves is obtained to reduce the amount of step at the parting line of the molded part.
The publication Metals Handbook, 8th Edition, vol. 5, published by the American Society for Metals, Metals Park, Ohio 44073, Copyright.COPYRGT. 1970, discloses on pages 164 and 165 jolt type and jolt-squeeze type molding machines and methods for making sand molds in which flasks are centered relative to patterns seated on a pattern support plate by the use of centering locator pins. After a flask is positioned by the centering locator pins, mold sand is poured into the flask so that the pattern is completely covered. Then the pattern support plate and the pattern with the surrounding flask and sand are jolted by a fluid operated piston mechanism so that the sand is compacted by its own weight around the pattern and is hardened. When this jolting is completed, push off pins are brought into contact with the lower surface of the flask and are stroked upward to push the flask and the contained hardened sand as a unit from the pattern to complete a mold half. In a jolt-squeeze molding machine, the sand is further compacted after jolting by raising the flask and sand against floating peen blocks extending from an upper compensating head. As with jolt type mold making machines, push off pins are employed to move the mold from the pattern plate, the pattern and the centering pins.